[Ti8Zr2O12(COO)16] Cluster: An Ideal Inorganic Building Unit for Photoactive Metal–Organic Frameworks

Yuan, Shuai; Qin, Jun‐Sheng; Xu, Hai-Qun; Su, Jie; Rossi, Daniel; Chen, Yuanping; Zhang, Liangliang; Lollar, Christina; Wang, Qi; Jiang, Hai‐Long; Son, Dong Hee; Xu, Hongyi; Huang, Zhehao; Zou, Xiaodong; Zhou, Hong‐Cai

doi:10.1021/acscentsci.7b00497

Cited by 219 publications

(204 citation statements)

References 41 publications

Supporting

Mentioning

194

Contrasting

Order By: Relevance

“…MUV-10(Ca) can be produced at ag ram-scale with yields close to 90 %b ys imple upscaling of reagents.W e selected al ist of different precursors commonly used in the synthesis of Ti-MOFs like Ti IV isopropoxide, [10,11] Cp 2 TiCl 2 [12] or ap reformed Ti 6 O 6 (O i Pr) 6 (O 2 C) 6 SBU. [14,26] Our experi-ments confirm that MUV-10(Ca) can be prepared as single crystals in all cases.T he precursor only affects their size moderately,that increases from 10 to 50 mmaccording to the sequence Cp 2 TiCl 2 > Ti 6 O 6 (O i Pr) 6…”

supporting

confidence: 72%

“…Communications of states diagram (DOS) suggests that this material is as emiconductor with ab and-gap of 3.1 eV,i ng ood agreement with the optical value extracted from diffuse reflectance spectroscopy (DRS) measurements according to the Kubelka-Munk function ( Figure S12). Similar to other Ti-MOFs, [12,14,18] the conduction band (CB) is dominated by Ti 3d orbitals,w hereas the valence band (VB) is composed mainly by 2p orbitals from the aromatic btc units.T he calculated band-gap is compatible with UV light photoactivity.T oprobe this point, we irradiated MUV-10(Ca) in dry deoxygenated THF with UV-B light (l = 280-315 nm). This produced achange in colour from white to dark brown in less than 2hours.This change remains stable with time and reverts back instantaneously by exposure of the solid to open air.As shown in Figure 3c,t he electron paramagnetic resonance (EPR) spectra of MUV-10(Ca) before and after irradiation shows the appearance of two signals only for the last.…”

Section: Angewandte Chemiementioning

confidence: 96%

See 1 more Smart Citation

Chemical Engineering of Photoactivity in Heterometallic Titanium–Organic Frameworks by Metal Doping

et al. 2018

View full text Add to dashboard Cite

We report an ew family of titanium-organic frameworks that enlarges the limited number of crystalline,p orous materials available for this metal. They are chemically robust and can be prepared as single crystals at multi-gram scale from multiple precursors.T heir heterometallic structure enables engineering of their photoactivity by metal doping rather than by linker functionalization. Compared to other methodologies based on the post-synthetic metallation of MOFs,our approach is well-fitted for controlling the positioning of dopants at an atomic level to gain more precise control over the band-gap and electronic properties of the porous solid. Changes in the band-gap are also rationalized with computational modelling and experimentally confirmed by photocatalytic H 2 production.Metal-organic frameworks (MOFs) are crystalline,molecular solids built from the linking of organic and inorganic components with coordinative bonds.M OFs feature incomparable chemical diversity and sizeable three-dimensional porosity ideal for applications like gas storage,s eparation or catalysis. [1,2] However,t hey often suffer from poor chemical stability-particularly in humid conditions-limiting their performance and preventing large-scale application. [3] Chemically robust MOFs can be produced by using basic nitrogenated linkers [4,5] or highly charged metals like Zr or Hf IV , [6][7][8] for endowing the framework with stronger metal-linker bonds less prone to hydrolysis.Compared to these metals,t itanium is naturally more abundant and features advantageous properties like low toxicity,redox versatility and potential photocatalytic activity. However,t he synthesis of carboxylate-bridged Ti IV ,c rystalline,p orous materials remains still as ynthetic challenge. [9] This is arguably due to the high reactivity of Ti precursors, which are prone to hydrolysis in the solvothermal conditions conventional to MOF synthesis to form amorphous TiO 2 .As result, only af ew Ti IV -MOFs like MIL-125, [10] NTU-9 [11] and COK-69 [12] synthesised from simple Ti precursors or PCN-22 [13] and -by using preformed clusters-have been prepared by direct reaction with polycarboxylate linkers.Applications of Ti-MOFs in photocatalysis are continuously expanding due to the unique properties that can arise from the combination of high surface area, crystallinity good photostability and photoactivity. [15,16] Moreover,compared to traditional inorganic semiconductors like TiO 2 ,photocatalytic activity can be finely tuned by direct modification of the organic linker to enhance light absorption in the visible region. This can be attained by functionalization of the linker with substituents to shift light absorption as exemplified by NH 2 -MIL-125. [17][18][19] Still, other routes often used with oxide semiconductors remain underexplored. Here we present an ew family of chemically robust, photoactive titaniumorganic frameworks coined MUV-10 (MUV = Materials of Universidad de Va lencia), that can be prepared as single crystals at multi-gram scale.C ompared to other...

show abstract

supporting

confidence: 72%

Section: Angewandte Chemiementioning

confidence: 96%

Chemical Engineering of Photoactivity in Heterometallic Titanium–Organic Frameworks by Metal Doping

et al. 2018

View full text Add to dashboard Cite

show abstract

“…2a, see ESI † for further details), which is a specialized technique for the structural determination of nanocrystals. 41,42 ZIF-C is a high density framework (Fig. 2b) non porous to N 2 (see Fig.…”

Section: Resultsmentioning

confidence: 99%

Phase dependent encapsulation and release profile of ZIF-based biocomposites

et al. 2020

View full text Add to dashboard Cite

show abstract

“…10–12 In this latter context, the development of MOF photocatalysts that mimic the reactivity of bulk TiO 2 is of timely interest. 13–19 …”

Section: ■Introductionmentioning

confidence: 99%

Bulk-to-Surface Proton-Coupled Electron Transfer Reactivity of the Metal–Organic Framework MIL-125

et al. 2018

View full text Add to dashboard Cite

Stoichiometric proton-coupled electron transfer (PCET) reactions of the metal−organic framework (MOF) MIL-125, Ti8O8(OH)4(bdc)6 (bdc = terephthalate), are described. In the presence of UV light and 2-propanol, MIL-125 was photoreduced to a maximum of 2(e−/H+) per Ti8 node. This stoichiometry was shown by subsequent titration of the photoreduced material with the 2,4,6-tri-tert-butylphenoxyl radical. This reaction occurred by PCET to give the corresponding phenol and the original, oxidized MOF. The high level of charging, and the independence of charging amount with particle size of the MOF samples, shows that the MOF was photocharged throughout the bulk and not only at the surface. NMR studies showed that the product phenol is too large to fit in the pores, so the phenoxyl reaction must have occurred at the surface. Attempts to oxidize photoreduced MIL-125 with pure electron acceptors resulted in multiple products, underscoring the importance of removing e− and H+ together. Our results require that the e− and H+ stored within the MOF architecture must both be mobile to transfer to the surface for reaction. Analogous studies on the soluble cluster Ti8O8(OOCtBu)16 support the notion that reduction occurs at the Ti8 MOF nodes and furthermore that this reduction occurs via e−/H+ (H-atom) equivalents. The soluble cluster also suggests degradation pathways for the MOFs under extended irradiation. The methods described are a facile characterization technique to study redox-active materials and should be broadly applicable to, for example, porous materials like MOFs.

show abstract

[Ti₈Zr₂O₁₂(COO)₁₆] Cluster: An Ideal Inorganic Building Unit for Photoactive Metal–Organic Frameworks

Cited by 219 publications

References 41 publications

Chemical Engineering of Photoactivity in Heterometallic Titanium–Organic Frameworks by Metal Doping

Chemical Engineering of Photoactivity in Heterometallic Titanium–Organic Frameworks by Metal Doping

Phase dependent encapsulation and release profile of ZIF-based biocomposites

Bulk-to-Surface Proton-Coupled Electron Transfer Reactivity of the Metal–Organic Framework MIL-125

Contact Info

Product

Resources

About